As well known in the art, a door hinge refers to an apparatus designed to allow a door to be opened/closed on a door frame. The door hinge is divided as a door hinge constructed to open and close the door in a left/right opening/closing method starting from one side, and a door hinge constructed to open and close the door in an up/down opening/closing method (that is, a lying down in front and coming out method) starting from an upper end.
The latter door hinge is used for a door of a gas oven or microwave oven that is electric home appliances. A conventional construction of the door hinge is shown in FIG. 1.
As shown in FIG. 1, the conventional door hinge 150 includes a fixing mount 110 installed at a door frame 100; and an activating mount 112 installed at the door 200, connecting by a hinge 126 with the fixing mount 110, rotating about the hinge 126, and opening and closing the door 200.
A guide unit 114 is provided between the fixing mount 110 and the activating mount 112, and guides an opening/closing operation of the door 200.
The guide unit 114 includes a connection plate 116 installed at the fixing mount 110; a rotation plate 120 connecting by a pin 118 with the connection plate 116 and rotating about the pin 118; and a guide pin 124 combining to a front end of the rotation plate 120 and moving up/down along the guide hole 122 provided at both side surfaces of the activating mount 112.
In the above constructed guide unit 114, when the activating mount 112 is rotated, the guide pin 124 vertically moves down along the guide hole 122 and at the same time, the rotation plate 118 connecting to the guide pin 124 rotates about the pin 118 depending on the movement of the guide pin 124 and guides the rotation of the activating mount 112. Thus, the door 200 can stably perform an opening operation.
However, the conventional door hinge 150 is expected to have drawbacks below in use.
First, there is a drawback in that, if the guide hole 122 is manufactured to have a straight-line shape as shown, a force is much needed in opening the door 200. In other words, due to a characteristic that the door 200 rotates about the hinge 126 and is lain down in front and opened, the door 200 pulls the guide pin 124 in its opening. Owing to the straight-line shape of the guide hole 122, the guide pin 124 strongly contacts with one side surface of the guide hole 122 by a pulling force of the door 200 in its movement, thereby generating a frictional force. This frictional force limits the guide pin 124 in its vertical movement, thereby causing a drawback of much needing the force in opening the door 200.
Further, it is required to open and stop the door 200 at a predetermined angle so as to check food in cooking, but there is a drawback that the conventional door hinge 150 is not provided with means for stopping the door 200 at a predetermined angle.